EP3428591B1

EP3428591B1 - Flame detector field of view verification via reverse infrared signaling

Info

Publication number: EP3428591B1
Application number: EP18183185.0A
Authority: EP
Inventors: Michael J. Grady; Venus Dantas
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2017-07-12
Filing date: 2018-07-12
Publication date: 2024-03-13
Anticipated expiration: 2038-07-12
Also published as: US20190019389A1; EP3428591A1; US10181244B1

Description

BACKGROUND

To prevent fires, the use of flame detectors may be incorporated into various environments, such as, for example, oil refineries, oil platforms/rigs, semiconductor fabrication plants, gas storage facilities, and/or power plants. These environments may require monitoring and an appropriate response to a fire or a potential fire situation. Flame detectors may detect a presence of a flame by sensing various spectral bands which may be emitted from the flame. Responses to a detected flame may include activating an alarm, shutting off a fuel line (e.g., a natural gas line), and/or triggering a fire suppression system.
WO2012/045996 , discloses a safety system providing a nodal system including a unit having a memory and an optical data receiver and a common control unit in combination with the unit. This includes a method of commissioning the system comprising the steps of activating the optical data receiver on the unit and transmitting an optical data signal to the unit thereby commissioning the unit.
WO2008/014592 discloses an infrared sensor security system comprising an infrared sensor located on a network as an IR transmitter and an IR receiver with a processor to control data packets to be transmitted by the EIR transmitter and receiver to provide bidirectional communication.

SUMMARY

The invention is set out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

FIG. 1 is a schematic illustration of an optical flame detector included in an optical flame detector operation verification system in accordance with embodiments of the present invention.
FIG. 2 is a schematic illustration of a portable infrared test receiver included in the optical flame detector operation verification system in accordance with embodiments of the present invention.
FIG. 3 is a schematic illustration of the optical flame detector operation verification system in accordance with embodiments of the present invention.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrative implementations of one or more embodiments are illustrated below, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or not yet in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, but may be modified within the scope of the appended claims.
The following brief definition of terms shall apply throughout the application:
The term "comprising" means including but not limited to, and should be interpreted in the manner it is typically used in the patent context;
The phrases "in one embodiment," "according to one embodiment," and the like generally mean that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention (importantly, such phrases do not necessarily refer to the same embodiment);
If the specification describes something as "exemplary" or an "example," it should be understood that refers to a non-exclusive example;
The terms "about" or "approximately" or the like, when used with a number, may mean that specific number, or alternatively, a range in proximity to the specific number, as understood by persons of skill in the art field; and
If the specification states a component or feature "may," "can," "could," "should," "would," "preferably," "possibly," "typically," "optionally," "for example," "often," or "might" (or other such language) be included or have a characteristic, that particular component or feature is not required to be included or to have the characteristic. Such component or feature may be optionally included in some embodiments, or it may be excluded.
Optical flame detectors ("OFDs") may have an effective field of view ("FOV"), and fires within the FOV may be detected, while fires outside the FOV are not likely to be detected. During installation of an OFD, a technician may align and aim the OFD to cover an intended area.
OFDs may be checked periodically in order to confirm reliable operation. There are a number of failure modes that might prevent proper operation of the OFD. For example, failure modes that might prevent operation can include, but are not limited to: 1) a window of the OFD may become dirty or obscured; 2) the OFD may be bumped so that its aim is no longer correct; 3) additional equipment may be installed in the optical path (e.g., FOV), blocking infrared ("IR") radiation and preventing flame detection.
A conventional solution to testing the operation of an OFD may involve sending a technician out with a test lamp (e.g., test IR source). The test lamp mimics a fire. That is, the test lamp must produce light approximately as intense as light produced by a fire. The technician may activate the test lamp (e.g., aim the test lamp at the OFD) from several locations and watch for an indicator light on the OFD. This may confirm that the IR path is clear. This may require two people because a second person may be in a control room disabling a response to a flame report. Therefore, this solution may be laborious, slow, and inefficient because the test lamp may be big and heavy, and may only have a 4 meter range (i.e., the test lamp must be near the OFD). Also, the test lamp may have a modest battery life. This may be short compared to a 50-60 meter range of the OFD. As a result, the use of a test lamp may not be capable of verifying the operation of the OFD at all distances within the operating range of the OFD. Thus, this solution may not be accurate in determining whether each location is within the FOV of the OFD.
The systems, methods, and/or devices of the disclosure may utilize reverse signaling to improve a signal to noise ratio by 1) Blocking out of band radiation at a portable infrared test receiver ("PTTR") with a near infrared region ("NIR") optical filter; 2) Blocking optical signals which may be modulated at an incorrect frequency relative to a digital infrared test signal ("DITS"). The DITS may utilize digital encoding (e.g., Manchester encoding). The DITS may modulate for a minority of an operation time of the OFD. That is, the DITS may be transmitted during a quiescent state of the OFD. This transmission of the DITS during the quiescent state may avoid creating a low frequency signal that might be in band for the OFD. This feature may allow the PITR to receive DITSs from multiple OFDs. Interpreting each DITS in an environment with multiple OFDs may be facilitated by both the PITR and the quiescent state DITS transmission.
The present invention relates to a system and a method for verifying operation verification of an OFD. The system and method incorporate/embed a digital infrared test signal source in the OFD. This digital infrared test signal source transmits a signal train (digital signal packet, DITS) to a test receiver (PITR). The DITS may include information/data such as, at least one of a serial number of the optical flame detector, a user's mnemonic name, sensor sensitivity, time (e.g., seconds) since a last reboot of the optical flame detector, a real time clock value of the optical flame detector, and current analog optical signal levels. The test receiver may be optically passive (e.g., test receiver may not transmit any signals such as a signal train). The test receiver can include a global positioning system ("GPS") and a logging capability (e.g., logging/storing data). This may make a verification procedure for OFD operation simpler. That is, a technician can simply walk to a potential flame source with the test receiver. The test receiver may then report a number of DITS it detects from various OFDs (e.g., a digital infrared test signal source of each OFD). This report can be either immediate on a display/user interface of the test receiver and/or logged/stored into an internal memory of the test receiver.
FIG. 1 is a schematic illustration of an OFD 100. The OFD 100 can include any suitable OFD configured to detect a fire/flame using optical detection techniques. In this regard, the OFD 100 serves to optically view a desired optical field for flames/fires, compose the transmitted DITS(s), and provide an alarm in the event that a flame/fire satisfying predetermined thresholds is detected. The OFD 100 may include a FOV from about 100° to about 170° relative to at least one axis (e.g., x-axis, y-axis, z-axis). The OFD 100 may detect flames at a distance ranging from about 0 meters to about 60 meters, relative to the position of the OFD 100. The OFD 100 may detect hydrocarbon and non-hydrocarbon based fires or flames. The operating temperature of the OFD 100 may be about -50°F to about 200°F.
The OFD 100 may include a housing 102 (e.g., which can be an explosion proof housing) which may include at least one of an ultraviolet ("UV") light sensor 104, a visible light sensor 106, an infrared ("IR") sensor 108 (e.g., analog IR receiver), and a digital infrared test signal source 109. A sensitivity for each of the sensors may be adjustable.
The housing 102 may include materials, such as, for example, aluminum and/or stainless steel. The housing 102 may include a window 107 positioned to cover the UV light sensor 104, the visible light sensor 106, and/or the IR sensor 108, and digital infrared test signal source 109. The window 107 may protect the sensors and the digital infrared test signal source 109.
The digital infrared test signal source 109 (e.g., an IR source/transmitter, etc.) emits/transmits a DITS recognizable by a test receiver. The DITS may be transmitted at an angle ranging from about 100° to about 170° relative to at least one axis (e.g., x-axis, y-axis, z-axis). That is, a spread of the DITS shall be similar to that of a coverage area included in the FOV of OFD 100. The digital infrared test signal source 109 may emit/transmit a DITS at a frequency ranging from about 30 kilohertz ("kHz") to about 60 kHz. The DITS may include data, such as, at least one of a serial number of the optical flame detector, a user's mnemonic name, sensor sensitivity, time since a last reboot of the optical flame detector, a real time clock value of the optical flame detector, and current analog optical signal levels. A transmitting range of the digital infrared test signal source 109 may substantially match that of a reception range of the OFD, and can range from about 0 meters to about 60 meters. That is, the digital infrared test signal source 109 may transmit a DITS up to a distance of about 60 meters. The DITS is detected by a test receiver.
FIG. 2 is a schematic illustration of PITR 113. The PITR 113 tests/verifies that the OFD 100 is operating as intended (e.g., monitoring the intended coverage area). The PITR 113 receives/processes the DITS. The PITR 113 may receive electromagnetic radiation (in an NIR), wherein a wavelength of the electromagnetic radiation may be between about 700 nanometers and about 1200 nanometers. The PITR 113 may be optically passive. In certain embodiments, the PITR 113 may be a low power electronic device which may allow it to be non-incendive (e.g., incapable, under normal operating conditions, of causing ignition of a flammable gas-air, vapor-air, and/or dust-air mixture due to arcing or thermal means). The PITR 113 may include a memory 115 and a user interface 116 (e.g., liquid crystal display ("LCD")), and optionally, a positioning or location module 114 (e.g., a global positioning system (GPS) receiver and module, a time of flight (TOF) positioning system, a received signal strength (RSS) positioning system, etc.). The PITR 113 may receive and/or process DITS from distances of up to about 60 meters. For example, the PITR 113 can receive and process DITS within the transmission range of the digital infrared test signal source 109. The PITR 113 may also calculate its location/position via the location module (e.g., via the location module 114). The PITR 113 may store the data included in the DITS within memory 115 and display this data on user interface 116. That is, memory 115 may store at least one of a serial number of the OFD 100, a user's mnemonic name, sensor sensitivity, time since a last reboot of the OFD 100, a real time clock value of the OFD 100, and current analog optical signal levels. The PITR 113 can receive and store information received from each OFD 100 within range.
In some embodiments, the DITS from more than one OFD may be received by the PITR 113 at a given location. The PITR 113 may be aimed/positioned at different viewing angles at a given location in order to determine which sources (e.g., OFDs with a digital infrared test signal source) are capable of viewing the PITR 113 at the given location. For example, the PITR 113 may be within view of two or more sources. During testing, as described in more detail herein, the PITR 113 can be positioned to receive a DITS from a first source, and once the DITS information is received, repositioned/aimed to receive a DITS from a second source. This process can be repeated until each source within view is detected. This process may allow for an indication that a particular piece of equipment or location is actually within view of one or more of the OFDs. DITS may convey data for a minority of the time; contain little low-frequency components that might interfere with the flame detection; and facilitate multiple OFDs transmitting the DITS at the same time without interference without optical selection.
FIG. 3 is a schematic illustration of an OFD FOV verification system 118 ("system 118"). System 118 includes the OFD 100 and the PITR 113. The OFD 100 may be positioned/installed on a structure 117 via a mount 119. The FOV of the OFD 100 include sa target area 120 (e.g., a location). That is, the OFD 100 is installed/positioned to scan target area 120 for a flame. The OFD 100 transmits a DITS, for example periodically or continuously. The PITR 113 is positioned at the target area 120. That is, to verify that target area 120 is within the FOV, a technician/user may position himself/herself with the PITR 113 at the target area 120. The target area 120 includes potential flame/fire sources, such as, for example, gas tanks, flammable materials, areas containing flammable materials, and the like.
If the FOV for the OFD 100 is correct (e.g., the potential flame source/target area is within the FOV), the PITR 113 receives the DITS and may indicate on the user interface 116 that the FOV is correct. If the FOV for the OFD 100 is incorrect (e.g., target area 120 is not within the FOV), the PITR 113 may not receive the DITS and may indicate that the FOV is incorrect on user interface 116 or not provide any indication of any received DITS. If the FOV is incorrect, a technician may correct the FOV by repositioning the OFD 100 to bring the target area 120 within the FOV. That is, based on receiving/not receiving the DITS, an indication can be made as to whether target area 120 is within the FOV of the OFD 100. For example, a green light displayed in user interface 116 may indicate if target area 120 is within the FOV of OFD 100. A red light displayed in user interface 116 may indicate if target area 120 is not within the FOV of the OFD 100.
In certain situations, window 107 (shown on FIG. 1) may become cloudy or non-transparent (e.g., obstructed) which may not allow the sensors to detect a flame and not allow the PITR 113 to receive a DITS. In this situation, the FOV may be correct, but the PITR 113 may indicate that the FOV is incorrect. A user/technician may need to examine the condition of window 107 after being notified that the FOV is incorrect, and may clean the window 107 as necessary, thereby allowing the sensors to detect a flame and allow PITR 113 to receive a DITS. In some instances, the DITS can be received, but the signal strength may be lower than expected and/or less than a threshold. Such a result may provide an indication that the FOV is correct, but that the window 107 is partially obstructed. That is, based on receiving/not receiving the DITS, an indication can be made as to whether OFD 100 is operating correctly (e.g., transmitting a DITS that is actually received). A green light displayed in user interface 116 may indicate proper/correct operation, whereas, a red light displayed in user interface 116 may indicate improper/incorrect operation.
In other scenarios, an object (e.g., equipment) may be positioned between target area 120 and OFD 100. This object may obstruct a line of sight (e.g., a signal transmission path)/FOV between the OFD 100 and the target area 120/ PITR 113, and may cause the PITR 113 to indicate an incorrect FOV and may not allow OFD 100 to detect a flame. Based on receiving/not receiving the DITS, an indication can be made as to whether the line of sight between the PITR 113 and the OFD 100 is obstructed or unobstructed. A technician/user may correct positioning of the OFD 100 or reposition the object to obtain the correct FOV. A green light displayed in user interface 116 may indicate an unobstructed line of sight/FOV between the OFD 100 and target area 120/ PITR 113, whereas, a red light displayed in user interface 116 may indicate an obstructed line of sight/FOV between the OFD 100 and target area 120/ PITR 113.
Benefits of systems, methods, and/or devices of the disclosure may include: 1) The test receiver may contain only low-power electronics which may allow it to be made non-incendive, 2) verification/testing may only require one person, 3) flame detection may not need to be interrupted for the test/verification, 4) the verification may be focused on the flame source instead of the flame detector, 5) the range of the IR source can be comparable to the range of the OFD, and 6) the facility owner may have a reliable record (e.g., data can be stored/reviewed in the receiver) confirming staff/technicians really did perform the verification/testing.

Claims

A system (118) for verifying operation of an optical flame detector (100), the system (118) comprising:
the optical flame detector (100), positioned in a manner to have a field of view which includes a location of potential fire, wherein the optical flame detector (100) comprises:
a digital infrared test signal source (109), wherein the digital infrared test signal source (109) is configured to transmit a digital infrared test signal in the direction of the location of the potential fire with a spread similar to that of a coverage area included in the field of view of the optical flame detector (100); and

at least one of an ultraviolet light sensor (104), a visible light sensor (106), and an infrared sensor (108); and

a portable infrared test receiver (113), positioned at the location of the potential fire and configured to receive the digital infrared test signal, wherein upon receipt of the digital infrared test signal the portable infrared test receiver (113) is configured to indicate that a location of potential fire is within a field of view of the optical flame detector (100).
The system (118) of claim 1, wherein the portable infrared test receiver (113) is configured to receive electromagnetic radiation, wherein a wavelength of the electromagnetic radiation is between 700 nanometers and 1200 nanometers.
The system (118) of claim 2, wherein a transmitting range for the digital infrared test signal source (109) is 0 meters to 60 meters.
The system (118) of claim 3, wherein the portable infrared test receiver (113) is positioned to receive signals at a distance from 0 meters to 60 meters.
The system (118) of claim 4, wherein the digital infrared test signal comprises at least one of a serial number of the optical flame detector (100), a user's mnemonic name, sensor sensitivity, time since a last reboot of the optical flame detector (100), a real time clock value of the optical flame detector (100), and current analog optical signal levels.
A method of verifying operation of an optical flame detector (100), the method comprising:
providing the optical flame detector (100), positioning it in a manner to have a field of view which includes a location of potential fire, wherein the optical flame detector (100) comprises:
a digital infrared test signal source (109), wherein the digital infrared test signal source (109) is configured to transmit a digital infrared test signal in the direction of the location of the potential fire with a spread similar to that of a coverage area included in the field of view of the optical flame detector (100); and

at least one of an ultraviolet light sensor (104), a visible light sensor (106), and an infrared sensor (108); and

providing a portable infrared test receiver (113) positioned at the location of the potential fire, wherein the portable infrared test receiver (113) is configured to receive the digital infrared test signal, wherein upon receipt of the digital infrared test signal the portable infrared test receiver (113) indicates whether a location of potential fire is within a field of view of the optical flame detector (100).
The method of claim 6, wherein the portable infrared test receiver (113) is configured to receive electromagnetic radiation, wherein a wavelength of the electromagnetic radiation is between 700 nanometers and 1200 nanometers.
The method of claim 7, wherein a transmitting range for the digital infrared test signal source (109) is 0 meters to 60 meters.
The method of claim 8, wherein the portable infrared test receiver (113) is positioned to receive signals at a distance from 0 meters to 60 meters.
The method of claim 9, wherein the digital infrared test signal comprises at least one of a serial number of the optical flame detector (100), a user's mnemonic name, sensor sensitivity, time since a last reboot of the optical flame detector (100), a real time clock value of the optical flame detector (100), and current analog optical signal levels.